There are many means in which therapeutic agents can be administered to a patient such a intravenous, intramuscular or intraperitoneal injections, naso-gastric tubes, transdermal patches and the like. Oral delivery systems have proven to be the easiest means for drug administration when the active can be absorbed into the digestive system as the tablet or oral suspension containing the drug of interest can be simply placed in the mouth and swallowed with or without water. Oral delivery also provides a relatively fast and efficient means to get the drug absorbed into the digestive system and dissolved into the bloodstream where the active drug is delivered to wherever necessary.
There have been numerous pharmaceutical vehicles developed over the years for the oral administration of drugs and therapeutic agents. Oral delivery systems have consisted of solid tablets that must be swallowed whole; solid tablets that dissolve in water and are then consumed; confectionery delivery systems in which the pharmaceutical agent is provided in a flavored, pleasant-tasting vehicle which is either chewed and ingested or is allowed to dissolve slowly in the mouth. The drug may also be dissolved and suspended in a liquid vehicle such as a flavored cough syrup which is easily swallowed.
One of the drawbacks to oral delivery systems however, is the situation wherein the drug to be administered is bitter, bad-tasting, odorous or in some manner organoleptically unpleasant. Many efforts have been made in the past to "taste mask" these compounds either through elaborate flavor and/or sweetener delivery systems, adsorption of the drug within another material or by encapsulation with a polymer, fat, carbohydrate or other like material. These taste-masking methods basically prevent the bitter tasting components of the drug from contacting the taste-buds during oral ingestion yet break down and release the active upon dissolution in the stomach. However, each of these methods also have their own drawbacks and the search remains for a fast-acting, non-offensive easily administrable oral drug delivery system.
U.S. Pat. No. 4,632,821 to Peters et al. discloses a medicament adsorbate in which a pharmaceutical such as an anti-tussive, antihistamine, decongestant and the like is adsorbed onto magnesium trisilicate particles having a flake-like structure and a surface area of at least 400 m.sup.2 /g. Whereas a number of pharmaceutical compositions are listed as being useful in the practice of the present invention, decongestants are the active of choice and are preferably formulated as a chewing gum or lozenge.
U.S. Pat. No. 4,647,459 also to Peters et al. discloses and claims a confectionery composition in which a pharmaceutical active is dispersed within a magnesium trisilicate adsorbate. The adsorbate is incorporated in a lozenge, tablet, toffee or nougat in an amount of from about 1.0% t 20% by weight.
U.S. Pat. No. 5,112,604 to Beurline et al. discloses an oral pharmaceutical liquid suspension comprised of theophylline as the active agent, silicon dioxide, a wetting agent and a hydrocolloid gum. The gum and silicon dioxide act to suspend the agent evenly throughout the liquid thereby insuring uniform dose dispersions. Whereas theophylline is the primary drug of interest anti-inflammatories, analgesics, antihistamines and others are also listed as suitable for use with the invention.
U.S. Pat. No. 4,650,663 also to Peters et al. discloses the preparation of an oral pharmaceutical delivery system in which an unpleasant tasting anti-tussive such as noscapine, carbetapentane citrate or clophedianol hydrochloride is adsorbed onto magnesium silicate flakes and incorporated into a chewable tablet or lozenge. The adsorbate allegedly masks the bitter taste to an almost negligible level to encourage better patient compliance.
U.K. Patent 1,388,786 assigned to the Schereer Corporation discloses an integral solid dosage carrier for pharmaceutical agents consisting of a gel-lattice structure that has been extruded into conventional configurations. The gel lattice consists of water-soluble colloidal hydrates such as gelatin, derivatives. The drug of interest is dissolved and mixed in the hydrate which is in liquid form. A plasticizer such as glycerin or triethyl citrate is then added which causes the gel lattice to form. Since it is relatively rigid containing from only 15%-20% water, no outer coating is needed for the dosage forms to retain their form and solubility over time.
It is an object of the present invention to provide a novel, oral delivery system that is chewable for rapid release of the active yet is pleasant tasting even when bitter tasting or otherwise unpalatable drug actives are involved. The drug is dispersed within an oral suspension comprising a medicament adsorbate and is then incorporated within a gelatin capsule. The soft, chewable capsules will encourage better patient compliance in difficult patients such as young children who are hesitant to swallow pills, caplets or capsules. The dosage form also provides excellent stability for the drug for extended longer term shelf life.